MAGNETOOPTICAL PROPERTIES OF MNBI AND MNBIAL

First-principle electronic structure calculations are used to describe the magneto-optical properties of MnBiAl alloys as a function of the Al concentration. The calculated Kerr rotation and ellipticity are in good agreement with the experimental data for MnBi. Due to lack of goo d structural information, the magnetooptical properties of MnBiAl are studied for Al as (a) an interstitial and (b) partially substituting f or Bi. The Kerr rotation of MnBi degrades with interstitial Al but rem ains about the same for a small amount of substitutional Al. The latte r result is in agreement with the experimental data. Thus, both theory and experiment are in agreement that Al does not improve the magneto- optical properties of MnBi.